A Taco Bell Mom or TBM is a mom hitting on another mom's husband inside of taco bell.
Usually started with a stare down and proceded with smiles, hair swooshing and laughter to draw attention from the dad while the other mom rolls her eyes.
Beware dad's of the TBM's...they're out to getcha.

I saw this Taco Bell Mom (TBM) and my daughter looked up and kicked me.